PHILADELPHIA (CBS) – Doctors at The Hospital at the University of Pennsylvania celebrated a milestone, the 1,000th heart transplant!

Penn’s transplant program is among the top three in the nation with 25 years of experience, performing between 50 and 60 heart transplants a year. While much still needs to be studied, there are folks walking around with a heart that wasn’t originally theirs.

Dr. Lee Goldberg, medical director for the University of Pennsylvania Heart Failure and Transplantation program, says the science of transplantation has improved tremendously over the years.

“Over the past several years there have been improvements to keep people alive with advanced heart failure so they are in better shape when they get to their transplant. And then at the time of transplant, we’re using newer medications and newer techniques to minimize the risks of the immunosuppression medicines to prevent rejection and also to prevent infection and some of the other side effects we saw years ago,” says Dr. Goldberg.

Dr. Goldberg says it takes a team of people to make a transplant happen; nurses, doctors, social workers and many others. He says it’s an honor to be a part of a medical marvel.

“Every time we transplant someone it’s a miracle,” says Dr. Goldberg.

Between 90 and 92 percent of patients are alive at a year and close to 70 percent are alive after 5 years, but he says they are continuously involved with studies to determine why some patients suffer acute rejection and others don’t.

By the way, the patient who received the 1,000th transplant is doing well!